Synthesis of superconducting cobalt oxyhydrates using a novel method: Electrolyzed and oxidized water

Chia-Jyi Liu, Tsung Hsien Wu, Lin Li Hsu, Jung Sheng Wang, Shu Yo Chen

Research output: Contribution to journalArticlepeer-review


By deintercalation of Na+ followed by inserting bilayers of water molecules into the host lattice, the layered cobalt oxide of γ-Na0.7CoO2 undergoes a topotactic transformation to a layered cobalt oxyhydrate of Na0.35(H2O)1.3CoO2-δ with the c-axis expanded from c ≈ 10.9 Å to c ≈ 19.6 Å. In this paper, we demonstrate that the superconducting phase of c ≈ 19.6 Å can be directly obtained by simply immersing γ-Na0.7CoO2 powders in electrolyzed/oxidized (EO) water, which is readily available from a commercial electrolyzed water generator. We found that high oxidation-reduction potential of EO water drives the oxidation of the cobalt ions accompanying by the formation of the superconductive c ≈ 19.6 Å phase. Our results demonstrate how EO water can be used to oxidize the cobalt ions and hence form superconducting cobalt oxyhydrates in a clean and simple way and may provide an economic and environment-friendly route to oxidize the transition metal of complex metal oxides.

Original languageEnglish
Pages (from-to)493-494
Number of pages2
JournalPhysica C: Superconductivity and its applications
Volume460-462 I
Issue numberSPEC. ISS.
Publication statusPublished - 2007 Sep 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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